Sign up to receive free email alerts when patent applications with chosen keywords are publishedSIGN UP

Abstract:

A solid state data storage assembly includes thermal interface material
that conducts heat away from electrical components of the assembly. In
some examples, the thermal interface material is positioned between a
printed circuit board assembly, which includes electrical components, and
a cover of a housing of the data storage assembly. The thermal interface
material may also provide shock protection for the data storage assembly
by at least one of increasing a stiffness of the data storage assembly,
absorbing some mechanical loads applied to the data storage assembly or
distributing the applied loads. In addition, in some examples, the
thermal interface material exhibits some tackiness, such that removal of
a thermal interface material from a data storage assembly and subsequent
repositioning of the thermal interface material within the data storage
assembly may provide a visual indication of tampering.

4. The assembly of claim 1, wherein the cover comprises a first cover, and
the housing comprises the first cover, a support frame and a second
cover, wherein the first and second covers are configured to connect to
the support frame to substantially enclose the printed circuit board
assembly.

5. The assembly of claim 4, wherein the thermal interface comprises a
first thermal interface positioned between the first cover and the
printed circuit board assembly, the system further comprising a second
thermal interface positioned between the second cover and the printed
circuit board assembly.

6. The assembly of claim 1, wherein the thermal interface is sized to
substantially cover the printed circuit board assembly when the thermal
interface is positioned between the cover and the printed circuit board
assembly.

7. The assembly of claim 1, wherein the thermal interface has a thickness
that is greater than or equal to a distance between the cover and the
printed circuit board assembly when the printed circuit board assembly is
substantially enclosed within the housing.

8. The assembly of claim 1, wherein the thermal interface contacts the
cover and the printed circuit board assembly when the printed circuit
board assembly and the thermal interface are substantially enclosed
within the housing.

9. The assembly of claim 1, wherein the solid state memory component
comprises at least one of a flash memory chip, a magnetic random access
memory chip, a static random access memory chip or a dynamic random
access memory chip.

10. The assembly of claim 1, wherein the thermal interface comprises a
peel strength in a range of about 0.44 Newton to about 2.22 Newton.

12. The assembly of claim 11, wherein the housing comprises a frame and a
cover, wherein the thermal interface contacts the cover and the printed
circuit board assembly when the thermally conductive material and the
printed circuit board assembly are substantially enclosed within the
housing.

13. The assembly of claim 11, wherein the thermally conductive material
comprises a thermal conductivity of comprising a thermal conductivity of
about 0.1 watts per meter-Kelvin (W/mK) to about 3.0 W/mK.

16. The assembly of claim 11, wherein the thermally conductive material
has a thickness that is greater than or equal to a distance between the
housing and the printed circuit board assembly when the printed circuit
board assembly is substantially enclosed within the housing.

18. A method comprising:placing a printed circuit board assembly within a
housing, wherein the printed circuit board assembly comprises a solid
state memory component;placing a thermal interface over the printed
circuit board assembly; andattaching a cover to the housing, wherein the
thermal interface is positioned between the cover and the printed circuit
board assembly.

19. The method of claim 18, wherein the thermally conductive material
comprises a thermal conductivity of comprising a thermal conductivity of
about 0.1 watts per meter-Kelvin (W/mK) to about 3.0 W/mK.

20. The method of claim 18, wherein attaching the cover to the housing
comprises compressing the thermal interface between the cover and the
printed circuit board assembly.

Description:

TECHNICAL FIELD

[0001]The invention relates to a data storage device, and more
particularly, a solid state data storage assembly.

BACKGROUND

[0002]Solid state data storage is an advancing technology for data storage
applications. Solid state data storage devices differ from non-solid
state devices in that they typically have no moving parts and include
memory chips to store data. Examples of solid state memory components
used for solid state data storage include flash memory and magnetic
random access memory (MRAM).

SUMMARY

[0003]In general, the disclosure is directed to solid state data storage
assembly that includes a printed circuit board assembly with electrical
components (e.g., a solid state memory component) and a thermally
conductive material (also referred to as a "thermal interface material")
that conducts heat away from the electrical components of the printed
circuit board assembly. In some examples, the thermally conductive
material is positioned between the printed circuit board assembly and a
cover of a housing of the solid state data storage assembly. In addition
to conducting heat away from the electrical components of the printed
circuit board assembly, the thermally conductive material may act as a
shock protector. That is, the thermally conductive material may help
mitigate or even prevent damage to the data storage assembly that may
result from the application of a shock to the data storage assembly.

[0004]In one aspect, the disclosure is directed to an assembly comprising
a printed circuit board assembly comprising a solid state memory
component, a housing comprising a cover, wherein the housing
substantially encloses the printed circuit board assembly, and a thermal
interface positioned between the cover and the printed circuit board
assembly. The thermal interface conducts heat away from the printed
circuit board assembly.

[0005]In another aspect, the disclosure is directed to a solid state drive
assembly comprising a printed circuit board assembly, a housing
substantially enclosing the printed circuit board assembly, and a
thermally conductive material positioned between the housing and the
printed circuit board assembly. The thermally conductive material
contacts the housing and the printed circuit board assembly.

[0006]In another aspect, the disclosure is directed to a method comprising
placing a printed circuit board assembly within a housing, wherein the
printed circuit board assembly comprises a solid state memory component,
placing a thermal interface over the printed circuit board assembly, and
attaching a cover to the housing, wherein the thermal interface is
positioned between the cover and the printed circuit board assembly.

[0007]The details of one or more examples of the invention are set forth
in the accompanying drawings and the description below. Other features,
objects, and advantages of the invention will be apparent from the
description and drawings, and from the claims.

BRIEF DESCRIPTION OF DRAWINGS

[0008]FIG. 1 is a perspective view of an example solid state data storage
assembly.

[0009]FIG. 2 is an exploded perspective view of the example solid state
data storage assembly of FIG. 1.

[0010]FIG. 3 is a perspective view of an example printed circuit board
assembly of the solid state data storage assembly of FIG. 1.

[0011]FIG. 4 is a flow diagram of an example technique for forming a solid
state data storage assembly that includes a thermal interface material
between a housing and a printed circuit board assembly.

DETAILED DESCRIPTION

[0012]FIG. 1 is a perspective view of an example solid state data storage
assembly 10, which can be a non-volatile data storage assembly. Solid
state data storage assembly 10 may also be referred to as a solid-state
drive. Data storage assembly 10 is suitable for use in various
applications, such as computing devices, portable electronic devices or
other devices that store data. Solid state data storage assembly 10
differs from non-solid state devices, such as disc drives, in that solid
state data storage assembly 10 typically does not have moving parts.

[0013]Data storage assembly 10 includes outer housing 12, which is defined
by frame 14, first cover 16, and a second cover 18 (shown in FIG. 2),
where first and second covers 16, 18 are mechanically coupled to opposite
sides of frame 12 to define a space within which electrical components of
data storage assembly 10 are enclosed. Covers 16, 18 can be mechanically
connected to housing 12 using any suitable technique, such as using one
or more screws, connection fingers, locking/clipping structures,
adhesives, rivets, other mechanical fasteners, welding (e.g., ultrasonic
welding) or combinations thereof. Housing 12 may be formed from any
suitable material, such as metal (e.g., aluminum), plastic, or other
suitable material or combinations thereof. Housing 12 substantially
encloses at least one printed circuit board assembly (not shown in FIG.
1), which includes electrical components, such as memory components
(e.g., flash memory, magnetic random access memory (MRAM), static random
access memory (SRAM) or dynamic random access memory (DRAM) chips) that
store data and one or more controllers.

[0014]FIG. 2 is an exploded perspective view of data storage assembly 10.
The example data storage assembly 10 shown in FIGS. 1 and 2 includes
frame 14, first cover 16, second cover 18, printed circuit board assembly
20, thermal interfaces 22, 24, and label 26. Label 26 may indicate the
parameters of data storage assembly 10, e.g., the memory capacity. In
other examples, data storage assembly 10 does not include label 26 or may
include more than one label.

[0015]As shown in FIG. 3, which is a schematic illustration of an example
printed circuit board assembly 20, printed circuit board assembly 20 can
include printed circuit board 30 and electrical components 32. Electrical
components 32 include components such as one or more controller chips
(e.g., controller integrated circuits) that control the storage and
retrieval of data by data storage assembly 10, one or more memory chips
(e.g., flash memory, MRAM, SRAM or DRAM chips), one or more passive
electrical components (e.g., capacitors or resistors), and the like.
Electrical components 32 are electrically and mechanically coupled to
printed circuit board 30 using any suitable technique, such as using
solder joints or connector pins that are positioned between electrical
contacts of electrical components 32 and electrical contacts on printed
circuit board 30. In the example shown in FIG. 3, electrical components
32 are soldered onto printed circuit board 20 using a surface mount
technology process. As a result, solder joints 34 are formed between each
electrical component 32 and printed circuit board 30.

[0016]Printed circuit board assembly 20 may include electrical contacts
that electrically connect to a plurality of input/output connectors 21,
which are each configured to provide as an interface with one or more
host device (e.g., a computer, a consumer electronic device, etc.). For
example, input/output connectors 21 can be configured to transmit data,
power and control signals to and from a host device. Example input/output
connectors 21 can, but need not include a service expansion shelf (SES)
connector, a serial advanced technology attachment (SATA) connector,
and/or a four pin test connector. Frame 14 of housing 12 defines opening
15 through which input/output connectors 21 may be accessed. Printed
circuit board assembly 20 can also be electrically connected to
additional connectors such as, but not limited to, a pin connector (e.g.,
a J1 connector, which is a 110-pin connector). The additional connectors
may be positioned on any suitable side of printed circuit board assembly
20, such as side 20A substantially opposite side 20B on which connector
21 is positioned.

[0017]Printed circuit board 30 may include electrical components on more
than one side. Thus, although electrical components 32 are shown on a
single side of printed circuit board 30 in the example shown in FIG. 3,
in other examples, electrical components 32 may be positioned on more
than one side of printed circuit board 30 (e.g., on opposite sides of
printed circuit board 30). In addition, although one printed circuit
board assembly 20 is shown in FIG. 2, in other examples, data storage
assembly 10 may include any suitable number of printed circuit board
assemblies, such as two, three or more. If data storage assembly 10
includes a plurality of printed circuit board assemblies, the printed
circuit board assemblies may be stacked in a z-axis direction (orthogonal
x-y-z axes are shown in FIGS. 1 and 2), stacked in the x-y plane or any
combination thereof.

[0018]During operation of data storage assembly 10, heat may be generated
by electrical components 32 of printed circuit board assembly 20. The
generation of heat from the operation of data storage assembly 10 may be
especially compounded when a plurality of data storage assemblies 10 are
positioned next to each other, e.g., in a device or in a server room or
other data center. As heat builds up within housing 12 (FIG. 1), the
performance of data storage assembly 10 may degrade and the useful life
of electrical components 32 may decrease due to the added stress on
components 32 from the relatively high temperature operating environment.

[0019]The issue of heat build-up becomes particularly pronounced when
housing 12 substantially encloses printed circuit board 20, e.g., as
shown in FIGS. 1 and 2, due to limited air circulation within housing 12
as well as the relative small size of housing 12. While one or both
covers 16, 18 may be removed from data storage assembly 10 in order to
help improve the heat conduction of data storage assembly 10, covers 16,
18 serve various purposes in assembly 10. As a result, other issues may
be arise as a result of removing one or both covers 16, 18 from assembly
10. For example, covers 16, 18 provides shock protection to assembly 10
by increasing the stiffness of assembly 10. In addition, covers 16, 18
helps protect printed circuit board 20 and its electrical components 32
from environmental contaminants, such as dust particles, liquids, and the
like. Thus, it may be undesirable to remove covers 16, 18 from housing 12
in some instances.

[0020]In order to help improve the heat conduction data storage assembly
10, data storage assembly 10 includes thermal interface 22 positioned
between printed circuit board assembly 20 and cover 16, and thermal
interface 24 positioned between printed circuit board assembly 20 and
cover 18. Thermal interfaces 22, 24 contact different sides of printed
circuit board assembly 20. In contrast to a thermally insulating
material, thermal interfaces 22, 24 each comprise a thermally conductive
material, which aids in the conduction of heat away from electrical
components 32 of printed circuit board assembly 20 and improves the
thermal transfer efficiency of data storage assembly 10. In some
examples, thermal interfaces 22, 24 exhibit a thermally conductivity of
about 0.1 watts per meter-Kelvin (W/mK) to about 3.0 W/mK, although other
thermal conductivities are contemplated. The conduction of heat away from
components 32 can help maintain the operational integrity of electrical
components 32 and increase the useful life of data storage assembly 10 by
decreasing the stress on components 32 that is generated from relatively
high operating temperatures. In some examples, thermal interfaces 22, 24
may each comprise a ceramic filled silicone elastomer. However, other
thermally conductive materials may also be used to form thermal
interfaces 22, 24.

[0021]In some examples, thermal interfaces 22, 24 are formed of a
substantially mechanically conformable material, such that thermal
interfaces 22, 24 are capable of substantially conforming to the
topography of printed circuit board assembly 20. In such examples, when
thermal interfaces 22, 24 are positioned over printed circuit board
assembly 20 and compressed, thermal interfaces 22, 24 may contact one or
more surfaces of printed circuit board assembly 20 (e.g., the surface of
electrical components 32). Increasing the contact between thermal
interfaces 22, 24 and printed circuit board assembly 20 with a
conformable material may be desirable in order to increase the conduction
of heat away from electrical components 32.

[0022]In addition to or instead of being formed from a substantially
conformable material, thermal interfaces 22, 24 may each define a
plurality of openings (e.g., cutaway portions) that are configured to
receive surface protrusions of printed circuit board assembly 20. The
surface protrusions may be formed by the placement of electrical
components 32 on printed circuit board 30 and extending from printed
circuit board 30. In this way, thermal interfaces 22, 24 may better
envelop electrical components 32 and increase the surface area for
contacting electrical components 32 and conducting heat away from
electrical components 32.

[0023]Thermal interfaces 22, 24 are each formed from one or more layers of
thermally conductive material, which may be substantially continuous in
order to define a path of low thermal resistance. In some examples,
thermal interfaces 22, 24 each comprise multiple layers of material that
may be stacked in a z-axis direction or multiple layers of material that
are positioned adjacent each other in the x-y plane.

[0024]In the example of data storage assembly 10 shown in FIG. 2, thermal
interfaces 22, 24 each define a structure having a stiffness that enables
thermal interfaces 22, 24 to be removed from housing 12 while maintaining
their structural integrity. For example, thermal interfaces 22, 24 may
each be configured such that they may be removed from housing 12 without
breaking apart or decomposing upon handling. As a result, thermal
interfaces 22, 24 may easily be introduced into and removed from housing
12 without generating particles or other contaminants that may affect the
operation of data storage assembly 10.

[0025]Configuring thermal interfaces 22, 24 such that they may each be
removed from housing 12 without leaving portions of thermally conductive
material within housing 12 may be useful, e.g., for purposes of accessing
electrical components 32 (FIG. 3) of printed circuit board assembly 20.
After assembly of data storage assembly 10, it may be useful to
periodically access electrical components 32 in order to repair data
storage assembly 10 or otherwise rework electrical components 32. Thermal
interfaces 22, 24 that are removable from data storage assembly 10
without substantially adversely affecting the properties of printed
circuit board assembly 20 provides a cost-effective technique for aiding
the conduction of heat away from printed circuit board assembly 20. In
some examples, thermal interfaces 22, 24 may be reused after being
removed from housing 12 (e.g., may be replaced in housing 12).

[0026]Thermal interfaces 22, 24 may have any suitable thickness. In some
examples, thermal interface layers 22, 24 each have a thickness of about
0.1 millimeters (mm) to about 2.0 mm. However, other thicknesses are
contemplated and may depend on the dimensions of the particular data
storage assembly 10. As described below, in some examples, a thickness of
each of thermal interface layers 22, 24 may be selected to fill a space
between covers 16, 18 and printed circuit board assembly 20 within
housing 12.

[0027]When data storage assembly 10 is assembled, there may be an air gap
between covers 16, 18 and printed circuit board assembly 20. This air gap
may act as a thermal insulator that impedes conduction of heat away
electrical components 32 (FIG. 3). As a result, heat generated by
components 32 may be retained within housing 12. In examples in which
thermal interfaces 22, 24 are sized to fill a space between covers 16,
18, respectively, and printed circuit board assembly 20, thermal
interfaces 22, 24 eliminate the air gaps between covers 16, 18 and
printed circuit board assembly 20. Thus, by contacting both covers 16, 18
and printed circuit board assembly 20, thermal interfaces 22, 24 each
provide a relatively low resistance thermal conduction path from printed
circuit board assembly 20, a source of heat, and the exterior of housing
12 (through covers 16, 18), to which the heat may be dissipated. In this
way, data storage assembly 10 is configured such that heat can be
dissipated through a relatively low resistance thermal pathway including
thermal interface material 22, 24, thereby reducing the operating
temperatures within housing 12.

[0028]The inclusion of thermal interfaces 22, 24 in housing 12 may
increase the number of potential uses of data storage assembly 10 and/or
decrease the restrictions on the operating environment requirements for
data storage assembly 10. For example, the increased ability of data
storage assembly 10 to conduct heat away from electrical components 32
may help decrease the cooling requirements for the applications in which
data storage assembly 10 is used. Depending on the application in which
data storage assembly 10 is used (e.g., within a device or a server
room), an external cooling source (e.g., a fan or an air conditioning
unit) may be used to help maintain a desirable operating temperature for
data storage assembly 10. The increased ability of data storage assembly
10 to conduct heat away from electrical components 32 may help increase
the tolerable operating temperature for data storage assembly 10, which
may decrease the cooling requirements for data storage assembly 10.

[0029]In addition to conducting heat away from electrical components 32 of
printed circuit board assembly 20, thermal interfaces 22, 24 may help
increase the mechanical robustness of data storage assembly 10. Due to
the configuration and placement of thermal interfaces 22, 24 within
housing 12, thermal interfaces 22, 24 help protect printed circuit board
assembly 20 from damage due to the application of a transient or
cumulative mechanical load on housing 12. In this way, thermal interfaces
22, 24 may also be referred to as a shock protector of printed circuit
board assembly 20. As described in further detail below, thermal
interfaces 22, 24 helps increase the stiffness of data storage assembly
10, as well as limits the movement of electrical components 32 (FIG. 3)
relative to printed circuit board 30 (FIG. 3) of printed circuit board
assembly 20.

[0030]Although solid state data storage assembly 10 can exhibit an
increased mechanical robustness compared to disc drives or other data
storage devices with moving parts, solid state data storage assembly 10
may still be sensitive to applied mechanical loads. Mechanical loads may
be exerted on housing 12 of data storage assembly 10, e.g., when data
storage assembly 10 is dropped or when an external force is applied to
housing 12. Printed circuit board 30 may flex or bend (e.g., from a
planar configuration to a nonplanar configuration) when a shock or
another type of mechanical load is applied to housing 12. The bending or
flexing of printed circuit board 30 may generate shear stresses that
disrupt the mechanical joints between electrical components 32 and
printed circuit board 30. For example, if solder joints 34 (FIG. 3) are
positioned between electrical components 32 and printed circuit board 30
(FIG. 3), the bending or flexing of printed circuit board 30 may result
in the deformation and shearing of solder joints 34. Some shear forces
may have a magnitude sufficient to deform at least some of the solder
joints 34 (or other mechanical connections between electrical components
32 and printed circuit board 30) to the point of failure. When the
mechanical connections between electrical components 32 and printed
circuit board 30 fail, electrical components 32 may break loose from
printed circuit board 30, which disrupts the electrical connection
between electrical components 32 and printed circuit board 30, and
compromises the ability of data storage assembly 10 to properly operate.

[0031]In some examples, thermal interfaces 22, 24 may be configured (e.g.,
sized and shaped) to help maintain the mechanical and electrical
connection between electrical components 32 and printed circuit board 30
of printed circuit board assembly 20 when a mechanical load is applied to
housing 12. In particular, in some examples, thermal interfaces 22, 24 is
sized and shaped to contact both printed circuit board assembly 20 and
covers 16, 18, respectively, such that the stiffness of printed circuit
board assembly 20 is effectively increased. Increasing the stiffness of
the printed circuit board assembly can help maintain the integrity of the
electrical and mechanical connections (e.g., connector pins or solder
joints) between electrical components 32 (FIG. 3) and printed circuit
board 30 (FIG. 3) of printed circuit board assembly 20 by minimizing the
stresses that are generated at the electrical and mechanical connections
when a mechanical load is applied to housing 12.

[0032]In particular, positioning thermal interfaces 22, 24 such thermal
interfaces 22, 24 contact both printed circuit board assembly 20 and
covers 16, 18, respectively, decreases the possibility that printed
circuit board 30 will bend or flex when a mechanical load is applied to
data storage assembly 10. The contact between covers 16, 18, thermal
interfaces 22, 24, respectively, and printed circuit board 30 creates a
composite or layered structure that effectively increases the rigidity of
data storage assembly 10 and decreases the amount of available space for
circuit board 30 to flex, thereby discouraging the bending or flexing of
printed circuit board 30. In this way, the positioning of thermal
interfaces 22, 24 in housing 12 increases the stiffness of printed
circuit board assembly 20, thereby minimizing the magnitude of shear
stresses that can result in the failure of the mechanical joints between
the electrical components and the printed circuit board.

[0033]In some examples, thermal interfaces 22, 24 fill the space between
printed circuit board assembly 20 and covers 16, 18, respectively. As a
result, when a transient mechanical load is applied to housing 12,
thermal interfaces 22, 24 may help hold electrical components 32 in place
on printed circuit board 30 by limiting the movement of electrical
components 32 relative to printed circuit board 30. This may further help
maintain the integrity of the electrical and mechanical connections
(e.g., connector pins or solder joints) between electrical components 32
(FIG. 3) and printed circuit board 30 (FIG. 3) of printed circuit board
assembly 20 when a mechanical load is applied to housing 12.

[0034]In addition, in some examples, thermal interfaces 22, 24 helps
distribute a force that is applied to housing 12 across printed circuit
board assembly 20, thereby reducing the concentration of mechanical
stress generated within printed circuit board assembly 20. In this way,
distributing the force across at least a part of printed circuit board
assembly 20 may reduce the possibility that the mechanical and electrical
joints between electrical components 32 and printed circuit board 30 may
break due to the application of external mechanical loads. In some cases,
thermal interfaces 22, 24 also dampens the mechanical loads (e.g.,
shocks) or vibrations that are applied to housing 12 and transmitted to
printed circuit board assembly 20. For example, thermal interfaces 22, 24
may each be formed of a material that has an elastomeric property that
enables thermal interfaces 22, 24 to absorb some mechanical loads that
are applied to housing 12.

[0035]In some examples, thermal interfaces 22, 24 are relatively tacky,
such that when thermal interfaces 22, 24 are positioned between printed
circuit board assembly 20 and covers 16, 18, respectively, and, sized to
fill the space between covers 16, 18, respectively, and printed circuit
board assembly 20, thermal interfaces 22, 24 adheres to the respective
cover 16, 18 and printed circuit board assembly 20. In some examples, at
least one of the thermal interfaces 22, 24 has a peel strength in a range
of about 0.44 Newton (about 0.1 pound-force) to about 2.22 Newton (0.5
pound-force) for a 5.08 centimeter (2 inch) by 8.89 centimeter (3.5 inch)
sample size relative to printed circuit board assembly 20. The adhesion
between thermal interfaces 22, 24 and the respective cover 16, 18 and
printed circuit board assembly 20 may also help increase the stiffness of
data storage assembly 10, which may further improve the shock protection
capability of thermal interfaces 22, 24.

[0036]In addition, the adhesion between thermal interfaces 22, 24 and the
respective cover 16, 18 and printed circuit board assembly 20 may provide
a visible indication that data storage assembly 10 has been tampered
with. For example, when thermal interfaces 22, 24 are formed from a
relatively tacky material, thermal interfaces 22, 24 may adhere to
printed circuit board assembly 20 and the respective cover 16, 18 when
data storage assembly 10 is first assembled. However, the material from
which thermal interfaces 22, 24 are formed may not allow thermal
interfaces 22, 24 to readhere as well (if at all) to the respective cover
16, 18 and printed circuit board assembly 20 after data storage assembly
10 is disassembled. Thus, if cover 16 and thermal interface 22 are
separated from the other components of data storage assembly 10, e.g., to
gain access to electrical components 32 of printed circuit board assembly
20, such tampering with data storage assembly 10 may be evidenced by the
lack of adhesion or a decrease in adhesion between thermal interface 22
and printed circuit board assembly 20. The same visual indication of
tampering may also be provided by thermal interface 24 if cover 18 and
thermal interface 24 are separated from the other components of data
storage assembly 10.

[0037]It may be desirable to determine whether the internal components of
data storage assembly 10 were exposed, thereby indicating tampering with
electrical components 32, for various purposes. For example, the
manufacturer of data storage assembly 10 may provide a buyer with a
limited warranty (e.g., covering manufacturing defects), which may be
nullified if the data storage assembly 10 is tampered with. Prior to
performing any warranty repairs on a data storage assembly 10, the
manufacturer may determine whether data storage assembly 10 has been
tampered with by examining the adhesion between thermal interfaces 22, 24
and covers 16, 18, respectively, and printed circuit board assembly 20. A
diminished adhesion (e.g., compared to an expected adhesion) between one
or both of the thermal interfaces and printed circuit board assembly 20
may indicate that the thermal interface has been removed from housing 12
and subsequently replaced in housing 12.

[0038]If thermal interfaces 22, 24 are formed from a substantially
conformable material, the manufacturer may also visually inspect thermal
interfaces 22, 24 to determine whether the pattern defined by the surface
of thermal interfaces 22, 24 facing printed circuit board assembly 20
substantially matches the expected pattern of a thermal interface 22 that
has been first removed from housing 12. If pattern defined by the surface
of one or both thermal interfaces 22, 24 differs from the expected
pattern, it may indicate that the thermal interface has been removed from
housing 12 and subsequently replaced in housing 12, thereby indicating
data storage assembly 10 has been tampered with.

Example

[0039]An experiment was performed to compare the shock resistance of a
solid state drive assembly including a thermally conductive interface
material compared to a solid state drive assembly that is otherwise
similar, but does not include a thermally conductive interface material.
A 1/2 sine pulse shock was applied to a solid state drive assembly
including a housing similar to housing 12 shown in FIGS. 1 and 2 and a
printed circuit board assembly including a plurality of electrical
components soldered to a printed circuit board. In particular, a solid
state drive assembly was dropped using a Lansmont Drop Tester (made
available by Lansmont Corporation of Monterey, Calif.), which helped
maintain the desired orientation of the solid state drive assembly as it
was dropped. The acceleration at which the drive assemblies were dropped
was determined using Model 352A25 and Model 352C22 accelerometers (made
available by PCB Piezotronics, Inc. of Depew, N.Y.).

[0040]A plurality of solid state drive assemblies each having a different
printed circuit board thickness and excluding a thermal interface
material were dropped in various orientations. Table 1 illustrates the
accelerations with which the solid state drive assemblies were dropped,
the thickness of the printed circuit board of the solid state drive
assembly, and a duration of each of the drops. In each of the iterations,
the solid state drive assembly was dropped with the solid state drive
assembly oriented such that the electrical components were facing in
either a positive z-axis direction ("memory array up") or a
negative-z-axis direction ("memory array down"), such that the
input-output (I/O) connector of the solid state drive assembly was face
down (e.g., electrical components facing in positive y-axis direction) or
face up (e.g., electrical components facing in negative y-axis
direction), or such that a four pin connector of the solid state drive
assembly was face up (e.g., electrical components facing in positive
x-axis direction) or face down (e.g., electrical components facing in
negative x-axis direction). In each of the solid state drive assemblies
that were dropped, the four pin connector and the I/O connector are
positioned on opposite sides of a housing of the solid state drive
assembly.

[0041]Iterations 1-3 shown in Table 1 represent the dropping of three
solid state drive assemblies each having a printed circuit board
thickness of about 0.76 millimeters (mm). Iterations 4-9 shown in Table 1
represent the dropping of a single solid state drive assembly having a
printed circuit board thickness of about 0.94 mm. In each subsequent drop
for iterations 4-9, the solid state drive assembly was rotated, such that
the consequences of dropping the solid state drive assembly in each of a
plurality of orientations was determined. Iterations 10-15 shown in Table
1 represent the dropping of a single solid state drive assembly having a
printed circuit board thickness of about 1.20 mm. In each subsequent drop
for iterations 10-15, the solid state drive assembly was rotated, such
that the consequences of dropping the solid state drive assembly in each
of a plurality of orientations was determined.

[0042]A solid state drive assembly was considered to fail the shock test
if, upon visual inspection, any of the electrical components were loose
or had fallen off the printed circuit board of the solid state drive
assembly.

[0043]As Table 1 demonstrates at least some of the solid state drive
assemblies that did not include a thermal interface material were unable
to withstand the applied shock. In particular, the solid state drive
assemblies showed a sensitivity to accelerations in a negative z-axis
direction.

[0044]A solid state drive assembly similar in configuration to those
tested to generate the data shown in Table 1 was modified to include a
thermal interface material between the covers of the housing and the
printed circuit board assembly. The thermal interface material was
Bergquist Gap Pad 2202, which is available from Bergquist Company of
Chanhassen, Minn., and was selected to have a thickness of about 0.051 mm
(about 0.020 inches) to fill the space between the covers of the housing
and the printed circuit board assembly. The solid state drive assembly
including a thermal interface material was dropped five times using the
Lansmont Drop Tester to determine whether the thermal interface material
helped improve the ability of the solid state drive assembly to withstand
a shock applied to the outer housing.

[0045]Table 2 illustrates the various accelerations with which the solid
state drive assembly was dropped, as well as the thickness the printed
circuit board and a duration of the drop. As with the testing performed
to generate the data shown in Table 1, the solid state drive assembly was
considered to fail the shock test if, upon visual inspection, any of the
electrical components (e.g., memory chips) were loose or had fallen off
the printed circuit board of the solid state drive assembly.

[0046]As Table 2 demonstrates, the solid state drive assembly including a
thermal interface material positioned between the covers of the housing
and the printed circuit board assembly was able to withstand
accelerations up to 1957 G when the solid state drive assembly was
dropped with the electrical components (e.g., the memory array) facing in
a positive z-axis direction. This suggests that the thermal interface
material improves the shock protection of a solid state drive assembly,
and, in particular, the electrical components of a printed circuit board
assembly.

[0047]FIG. 4 is a flow diagram of an example technique for forming solid
state data storage assembly 10. In accordance with the technique shown in
FIG. 4, one or more printed circuit board assemblies 20 are placed within
frame 14 (40). The one or more printed circuit board assemblies 20 can be
attached to frame 14 using any suitable technique. In some examples,
frame 14 includes side rails, brackets or other mechanical structures
that align with and support the one or more printed circuit board
assemblies 20. The one or more printed circuit board assemblies 20 can be
mechanically connected to these side rails, brackets or other mechanical
structures of frame 14. For example, the one or more printed circuit
board assemblies can be connected to frame 14 using one or more screws,
connection fingers, locking/clipping structures, adhesives, rivets, other
mechanical fasteners, welding (e.g., ultrasonic welding) or combinations
thereof.

[0048]After placing one or more printed circuit board assemblies 20 within
frame 14, thermally conductive material defining thermal interface 22 is
placed over printed circuit board assembly 20 (42). In some examples, the
thermally conductive material is placed over printed circuit board
assembly 20 such that the major surface of printed circuit board assembly
20 that is exposed by frame 14 is substantially covered by the thermally
conductive material. In this way, thermal interface 22 may be sized and
shaped to substantially cover printed circuit board assembly 20. After
the thermally conductive material is placed over printed circuit board
assembly 20 to define thermal interface 22 (42), cover 16 is positioned
over thermal interface 22 (44) and attached to frame 14 (46). Cover 16
can be attached to frame 14 using any suitable technique, such as screws,
connection fingers, locking/clipping structures, adhesives, rivets, other
mechanical fasteners, welding (e.g., ultrasonic welding) or combinations
thereof.

[0049]Thermally conductive material can be pre-attached to cover 16 or can
separate from cover 16 prior to inclusion in housing 12. In some
examples, thermal interface 22 has a thickness that is greater than or
equal to a distance between cover 16 and printed circuit board assembly
20. As a result, when cover 16 is positioned over thermal interface 22
(44) and attached to frame 14 (46), thermal interface 22 substantially
fills the space between cover 16 and printed circuit board assembly 22.
In addition, in examples in which thermal interface 22 has a thickness
that is greater than a distance between cover 16 and printed circuit
board assembly 22, the attachment of cover 16 to frame 14 compresses
thermally interface 22, which may further increase the stiffness of data
storage assembly 10. As discussed above, this may help reduce the
possibility that printed circuit board 30 (FIG. 3) bends or flexes in the
z-axis direction, which can help maintain the integrity of the mechanical
and electrical connection between electrical components 32 (FIG. 3) and
printed circuit board 30.

[0050]In some examples of data storage assembly 10, housing 12 may include
a single cover. In other examples, however, housing 12 of data storage
assembly 10 includes two covers (e.g., as shown in FIG. 1) or more than
two covers. Thus, in some examples of the technique shown in FIG. 4, a
thermal conductive material may also be placed over the opposite surface
of printed circuit board assembly 20 to define second thermal interface
24, and second cover 18 may subsequently be positioned over second
thermal interface 24 and attached to frame 14.

[0051]Various examples have been described. These and other examples are
within the scope of the following claims.